Generally, the term “hula-hoop” refers to equipment for playing or improving health by turning a ring-shaped hoop around the hips, as in a hula-dance. The hula-hoop is used as waist exercise equipment for strengthening the muscles of the waist.
The hula-hoop usually has the shape of a simple ring. In addition, a hula-hoop having on the inner circumferential surface thereof acupressure protrusions has become widely popular.
When the hula-hoop is rotated, the waist is pressed or massaged in a horizontal direction, but no pressing force acts on the waist in a vertical direction.
More improved hula-hoops are disclosed in Korean U.M. Registration No. 20-0210351 and No. 20-0249553. In Korean U.M. Registration No. 20-0210351, two ring-shaped hula-hoops are coupled to each other. Meanwhile, in Korean U.M. Registration No. 20-0249553, a hula-hoop is constructed to have a wavy shape, thus increasing the area of contact with the waist.
The conventional hula-hoops are advantageous in that the area of contact with the body (waist) is increased when the hula-hoop is rotated. However, the conventional hula-hoops are problematic in that no pressing force acts in a vertical direction, but pressing force acts only in a horizontal direction, as in the prior art.